Preheat the oven to 140C/285F. Line and grease a 18cm or 20 cm (8 inch) square cake tin
Place the eggs in the bowl of a kitchen stand mixer and beat for 5 minutes, or until fluffy.
Add the maple syrup and vanilla extract and beat on high until smooth.
Mash/purée the pumpkin and add to the mixture, beating on high.
In a separate bowl, sift together the dry ingredients. Add the milk to the vinegar and stir until combined.
Add the milk and dry ingredients alternatively, starting/ending with the milk.
Pour into the cake tin and bake for 1 hour, 50 minutes to 2 hours or until cooked through. The cake will be very moist.
Immediately put the cake in the freezer for 1 hour.
Remove and keep at room temperature until cooled completely and remove from the tin.
Frost with Honey Frosting and dust with Cinnamon.
The cake will become denser as it ages. Store in the fridge.